The first milestone in the development of electricity meters is the replacement of electromechanical meters with solid-state electronic electricity meters. Electronic electricity meters measure power using highly integrated components (such as ADE516x1, ADE556x2, ADE716x3,ADE756x4, and ADE77xx5 series of power metering ICs). These components convert momentary voltages and currents into digital quantities through a high-precision ∑-∆ A DC, and then calculate the product of voltage and current to reach instantaneous power in watts. The instantaneous power is integrated over time to arrive at the value of the power consumed, which is usually measured in kilowatt hours (kWh).The energy consumption data is displayed on a liquid crystal display (LCD), as shown in Figure 2.

Electronic electricity meters have many advantages. In addition to measuring instantaneous power, it can measure other parameters,such as power factor and reactive power. It measures and stores data every other specific time period, which allows power companies to provide time-phase billing services. As a result, clever users use major appliances such as washing machines and dryers during low-rate off-peak periods, saving electricity bill sand reducing demand for electricity during peak periods, and power companies avoid building new power plants. Electronic meters are also not affected by external magnetic fields or the placement angle of the meter itself, so they are better at preventing theft than electromechanical meters. In addition,electronic electricity meters are highly reliable.